Reduction of oxalic acid to glyoxylic acid electrochemically using a selective non-crosslinked sulfonated polystyrene membrane

Abstract

The electrochemical reduction of oxalic acid to glyoxylic acid has been studied using a selective membrane made of non-crosslinked sulfonated polystyrene in a cell equipped with lead cathode and lead dioxide anode. A chemical yield of 80.04% ± 2.34 is obtained with 99.42% ± 4.87 selectivity after 150 minutes of reaction under optimum conditions. Increased current density resulted in a significant improvement in conversion ratio and rate has been observed. The byproduct, glycolic acid, forms after more than 120 minutes in conjunction with decreasing selectivity of glyoxalic acid. Its formation is supported by current density and temperature. IR, EDX, and SEM techniques characterize the prepared film, it is assigned by degree of sulfonation, the ion exchange capacity, the water absorption ratio, the swelling ratio, and the ratio of water to sulfonic groups’ molecules has been considered. The results indicate that, the success of sulfonation process and under the transport of the proton through the membrane in the form of hydronium. Prepared SPS membrane exhibited comparable performance to its analogue. The industrial Nafion117 membrane exhibits enduring product selectivity, while SPS membrane shows higher electrical yield due to a greater ion exchange capacity.